From WO 2005/092613 A2 a printing press that preferably prints in a multicolor printing process is known, comprising at least one inking unit having a metering device, wherein the metering device of the inking unit is regulated by a control device, wherein the control device is connected to a preferably optical detection device, wherein the detection device uses a sensor oriented toward a surface of a print substrate imprinted in the printing press to detect the quality of the printing.
DE 42 38 557 A1 describes a method for adjusting the amount of dampening agent in an offset rotary printing press, in which a densitometer is used to measure ink density in adjoining inking zones of a print control strip, wherein for a specific color, the ratio between a predefined number of inking zones and the number of inking zones in the control strip in which the respective ink density has changed at the same time is determined.
From EP 0 741 026 A2 a method for inspecting images and supplying ink to printed products of a printing press is known, wherein an optical detection device detects printed images of the printed products, wherein the printed images of the printed products are subdivided into zones corresponding to the zonal divisions of an inking unit of the printing press, wherein in one of multiple assessment steps for each of the imprinted colors, fields of one zone are compared with fields of neighboring zones, and are checked for similar color deviation, wherein a regulation of ink will be initiated only if the current supplying of ink is found to be the cause of a determined color deviation.
From EP 1 437 222 A1, a method for printing a print control strip comprising multiple measuring fields is known, wherein the ink densities applied to the individual measuring fields on a print substrate are measured and are used for regulating the ink in a printing press, wherein within the same inking zone, which extends longitudinally in the direction of transport of the print substrate, measuring fields arranged side by side transversely to the direction of transport of said substrate are arranged into three groups of measuring fields, wherein in each group the measuring fields assigned to the inks being used in the print operation are arranged in the same order side by side, wherein in each case a ratio or a difference between an ink density of a specific ink measured in a measuring field of the center group and the two other ink densities of the same ink, each measured in a measuring field of one of the two other groups, is formed, wherein it is ascertained whether the determined ratio or the determined difference is within permissible predefined limits. A result that lies outside of these predefined limits is evaluated as scumming or smearing, for example.
From EP 1 084 843 A1 a device for measuring printed products in densitometric terms is known, wherein measurements obtained from a densitometer measuring head are calculated on the basis of predefined set values and are used as control commands for regulating the ink in a printing press, wherein, using an evaluation unit situated downstream of the densitometer and comprising a computer unit, the ink density values for one measuring field are compared with those of adjacent measuring fields of the same ink and measuring field type (full-tone or halftone).
From DE 10 2004 003 612 A1, a method for evaluating an image of a predetermined section of a printed product is known, in which an image of a predetermined section of the printed product is recorded by a camera using an electronic surface image sensor, in which an image recorded by the image sensor is read out and processed by an electronic evaluation unit, wherein intensity signals recorded from first predetermined fields within the section are linked by calculation to reference data values, which represent a measurement of the intensity of the diffuse light reflected from unprinted regions of the printed product, wherein first an image of a white reference is recorded, and from the intensity signals of said image, basic reference data for the entire section are derived, wherein with each evaluation of an image of the predetermined section, correction data are derived from intensity signals recorded from second predetermined fields within the section, and wherein, before the intensity signals recorded from the first predetermined fields within the predetermined section are linked by calculation to the reference data, the latter are obtained by linking the basic reference data to the correction data by calculation.
From DE 10 2004 021 601 A1 a method for use in a printing press comprising at least one inking unit is known, wherein at least one setting of the relevant inking unit during an ongoing printing process of the printing press, in which a surface of a print substrate is imprinted, can be modified by a control device using at least one measured value acquired during said printing process of the printing press, wherein the control device assesses the plausibility of the acquired measured value before adjusting the setting of the relevant inking unit. To assess the plausibility of the measured values, for example, threshold values for a deviation in the ink density range, for example, are defined, which may not be exceeded by two sequential or spatially adjacent, coincident measured values.
DE 38 29 341 A1 describes a method for acquiring data about a printed image for the purpose of regulating the supply of ink in printing presses, which method uses a densitometer for generating the data, a memory for collecting the data or a spectral photometer and a computer for evaluating the data, in order to control an ink metering device which is divided into zones, wherein the print image is divided into image zones based upon its structure, each zone optionally extending over a different number of zones of the ink metering device, and wherein the image zone data are stored in an image zone memory device, wherein in the image region of each image zone, ink density values are measured by the densitometer or spectral photometer of said zone, wherein the data obtained in this manner are transmitted to the computer, which checks them for completeness and accuracy, wherein if the result of the check is positive, the data are stored in an image data memory device, the densitometer or spectral photometer is cleared for the next measurement, and the next step within a measuring cycle is initiated, or wherein if the result of the data check is negative, an error message is sent and the densitometer is cleared again for the same step in the measuring cycle.
From DE 35 43 444 A1, a method for achieving a uniform print result using an autotypical multicolor printing press is known, in which the supply of inks to adjacent inking zones of a print substrate can be adjusted by means of adjustment elements, and in which, to regulate the printing process, full-tone densities and/or halftone dot sizes in measuring fields imprinted together within the inking zones are repeatedly determined, and if said densities and/or dot sizes fall outside of permissible ranges assigned to them, corrections to the printing process are made by actuating the adjustment elements, wherein to maintain inking equilibrium during the printing process, selected ratios of full-tone densities and/or halftone dot sizes of different inks to one another are also repeatedly determined, and if said selected ratios fall out outside of permissible ranges assigned to them, corrections to the printing process are made by actuating the control elements.
DD 80 046 A1 describes a method for identifying waste copies in rotary printing, wherein one or more photoelectric scanners or illuminating and measuring beams measure the reflective capacity of a non-imprinted area of the paper from one or both sides, wherein this method allows the measuring signal to be used prior to measuring in order to detect unprinted copies or copies having insufficient inking.